Galvanometer.



No. 705,|86. Patented July 22. |902. A. ZELENY.

GALVANOMETEB.

`Application led Jan. 20, 1902.)

(No Model.)

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QATENT unica.

` ANTHONY -ZELENY, OF MINNEAPOLIS-MINNESOTA, ASSIGNOR OF ONE-HALF TO C. E. THAYER, OF MINNEAPOLIS, MINNESOTA.v

GALVANOMETER.

SPECIFICATION forming part of Letters Patent No. 705,186, dated July 22, 1902. Application filed January 20,1902. Serial No. 90.401. (No model.)

`useful Improvements in Galvanometers; and

Iy do hereby declare the following to be a full, clear, and exact description of the invention,

such as will enable others skilled in the art to which it appertains to make and use the same.

My present invention has for its object to provide an improved galvanometer for use in connection with thermo-electric couples or circuits, and is particularly directed to the improvement of the galvanometer-scale whereby the temperature of the opposing or socalled unknown-temperature junction will be directly indicated on the scale in degrees, fractions, or multiples thereof.

To the above ends the invention consists of the novel devices and combinationsof devices hereinafter described, and defined in the claims.

I will rst describe my invention as applied to what is known to the trade as the Rowland DArsonval galvanometer.

The application of the device as above stated is illustrated in the accompanying drawings, wherein like characters indicate like parts throughout the several views.

Figure 1 is a perspective view of a galvanometer of the type above indicated, the thermo-electric couple being indicated in diagram. Fig. 2 is fa detail view, in front elevation, with some parts sectioned and others broken away, showing the interior mechanism of a galvanometer. Fig. 3 is a face view of the improved scale, and Fig. 4 is a detail in front elevation showing the pinion and a portion of the cooperating rack for adjusting the scale-bar.

Of the ordinary parts of the galvanometer the numeral 1 indicates the telescope-support, the numeral the base-plate, the numeral 3 the telescope, the numeral 4 the adjustable scale-bar, the numeral 5 the permanent magnet, the numeral 6 the needle-coil, the charr acter 2 an' inclosing case, and the numeral 7 the indicating-mirror, which mirror is oscil-.

lated'by said needle-coil. The scale-bar 4 is made adjustable in the ordinary way by means of a rack 8 and a thu rnb-piece 9, which thumb-piece is provided with a pinion 9a, meshing with the teeth of said rack, as shown in Fig. 4. j

The thermo-electric couple or circuit illustrated will be assumed to be aiforded by a German-silver wire a, and copper wires b, which wires are united to form thermo-elec-- tric j unctions f and g. The junction f will be treated as the known-temperature junction and thejunction g as the opposing or unknown-temperature junction. In one of the copper' wires b there is,l as shown, a switchkey b. The extended end of one of the copper wires b is shown as connected to the per-l manent magnet 5 and from thence through theneedle-supporting fiber 10 with the upper terminal of the needle-coil 6. The extended end of the other copper wire b is shown as connected to an insulated contact-piece 11 and from thence :through a coiled conductor 12 with the lower terminal of the said coil.

The numeral 13 indicatesa tubular support secured at its lower end 'to the permanent magnet 5 and provided with an adjusting-rod 14,'to which, as shown, the upper end of the ber 10 is secured.

rlhe numerals l5 and 16 indicate, respectively, the relatively xed and movable members of a pair of clamping-springs for securing the needle-coil 6 against movements when the instrument is being transported'.

The numeral 17 indicates an adj usting-rod shown as guided by the magnet 5 and subject to an adjusting-nut 18 and provided at its lower end with a finger 19, attached to the free end of the clamp 16. When the rod 17 is drawn upward by the nut 18, it will clamp the needle-coil 6 against the clamp 15.

/Vithv almost all combinations of metals which may be used in the thermo-electric couple onedegree variation of temperature at high temperatures will give eithera materially greater ormaterially less iiow of current than will the saine variation of temperature at low temperatures. To illustrate by one degree of variation of temperature -beloo tween the thermo-electric junctions when thesaid junctions are respectively 99.and fgufi ` which is proportionately graduated and in Lat which any particular division thereof is equal to the deflection produced by the current when the temperatures of the two opposing junctions are respectively those indicated by the bounding-lines of the particular division. Such a scale is illustrated in Fig. 3. On this scale the'graduat-ions are niade in degrees, and as the scale illustrated is to be used in connection with a reading-telescope and mirror the numbering of the scale is reversed, so as to appear natural when reflected from the galvanometer-rnirror and seen through the telescope.

The principles involved in the construction of the scale' and the relations thereof to the other parts of the galvanometer and to the thermo-electric couple will be made further apparent by a description of the operation.

We will assume for illustration that the known temperature of the junction fis found to be 80. Hence while the circuit is broken the scale will be adjusted until its gradua- 'tion-markl 80 is caused to coincide with the cross-hair ci the telescope. The circuit is then closed bythe key b' or other device, and the current which will then flow, due to the difference in temperature between the two junctionsfand g, will cause such a deflection of the indicating-mirror as will indicate in degrees on the scale the temperature of the said opposingjunction g. Otherwise stated, ifthe cross-hair line of the telescope is caused to coincide with the graduation indicating 600 on the scale then the reader will know that 60 is the temperature at the said junction g.

As a general statement it maybe said that while the circuit is open the scale is always adjusted until the scale graduation -correspending to the temperature of the knownteinperature junction f is caused to coincide with the cross-hair of the telescope, and the circuit being ciosed the deflection will indicate the temperature of the unknown or opposing junction g.

As already indicatede different combinations of metals may be used to forni the thermo-electric couples. if copper and iron are used, a variation in deiiection at different temperatures will be obtained which is approximately reverse to that obtained by the use of copper and German silver. @n the other hand, bv the use of German silver and iron an approximately unifor scale maybe used, inasmuch asa git/er perature loi.

romeo thus becomes apparent that the scale forwany particular combination of metals must be precalculated and proportioned to the delicotions which will be produced by given variations in temperature.

it will of course he understood that scales designed in accordance with inyinvention, as abovey set forth, may be applied to various forms of galvanometers, ammeters, voltnieters, electrometers, and similar reading instruments. ln fact, the term galvanometer is herein used in a Very broad sense and is intended to include all such instruments.

The term indicator is herein used in a broad sense and is intended to include pointers, reiiectors, and other devices which serve as an index or to give a reading on the galf vanometer-scale.

What l claim, and desire to secure by Letters Patent of the United States, is as follows:

l. The combination with a thermo-electric couple, of a galvanometer having a readingscale graduated in degrees of temperature and set, when the circuit is open, so as to indicate the temperature of the cknown-tennperature junction, whereby, when the circuit is closed, the temperature ot' the opposing junction will be directly indicated, in degrecs, on said scale.

2. The combination with a thermo-electric couple, of a galvanometer having a readingscale and an indicator, one of which is adjustable with respect to the other, and which scale is graduated in degrees of temperature and, by said adjustment, is adapted to be set, when the circuit is open, to indicate the temperature of the known-temperature junctionjiwhereby, when the circuit is closed, the teinperatu re of the opposing junction will be directly indicated, in degrees, on said scale.

3. The combination with a therinoelectric couple, of a galvanoineter having a readingscale variably graduated,each division thereof being equal to the deflection produced when the temperatures of the two opposing tions are, respectively, those indicated bythe numbers at the bounding-lines of that particular division, or by the numbers that said bounding-lines represent.

4. The combination with a thermo-electric couple, of a galvanoineter having a readingscale graduated in, degrees of temperature, each division thereol being.;l equal to the deilection produced when the temper the two opposing', junctions pcc fely, those indicated bythe numbers at the hounding-lines of that particular division., oi "si the said houndirr iation w spectvely, those indicated by the numbers degrees, on said scale, when the circuit is at the bounding-lines o that particular dclosed. ro Vision, or by the numbers that said bound- InA testimony whereof I afx my signature ing-lines represent, whereby the said scale in presence of two Witnesses. l

being set, when the circuit is open, to ind- ANTHONY ZELENY.

cate the temperature of the knoWn-temper- Vftnesses:

'sature junction, the temperature of the op- ELIZABETH KELIHER,

posing-junction will be direotlyindicated, in F. D. MERCHANT. 

